Method and means for forming bimetal strips for bearing sleeves



Jan. 16, 1934. B. STOCKFLETH ET AL METHOD AND MEANS FOR FORMING BIMETAL STRIPS FOR BEARING SLEEVES Original Filed Dec. 15, 1930 2 Sheets-Sheet 1 Jan. 16, 1934- B. STOCKFLETH El AL 1,943,351

METHOD AND MEANS EUR F ORNING BIMETAL STRIP$.FQR BEARING SLEEVES Original Fi led Dec. 15, 1930 2 Sheets- Sheet 2 mew er @52 0 @[74 G58, 9

ml,fiermoac Patented Jan. 16, 1934 METHOD AND MEANS FOR FORMING BIMETAL STRIPS FOR BEARING SLEEVES Berger Stockfleth and Glenn L. Sherwood, Niles, Mich assignors, by mesne assignments, to The Cleveland Graphite Bronze Company, Cleveland, Ohio, a corporation of Ohio Application December 15, 1930, Serial No. 502,443 Renewed April 1, 1933 14 Claims. (01. 207-11) This invention relates to an improved means and methods for making bi-metal strips and has special reference to the production of bi-metal strips for use in making bearing sleeves.

The bi-metal strips to which this invention relates usually consist of thin, fiat, steel strips with Babbitt metal applied to one side.

This novel method contemplates the provision of the thin metal strips for the backs with at least one side roughened and the strips coated with a suitable bonding metal, such as tin.

The strips are forcibly passed through openings arranged in relation to a quantity of the Babbitt metal in molten condition. The openings are arranged to prevent the outflow of the Babbitt metal at the entering side and .to permit a layer of the Babbitt metal to emerge with the backing strip at the exit side. As the strip passes through the exit die opening, the Babbitt metal is congealed but not hardened, that is, it is still malleable and before the strip leaves the machine it may be, and preferably is, forced through a die by which the metal, especially the bearing metal, is compressed. This action is similar to a wire drawing operation and accurately sizes the bi-metal strip.

The application of the bearing metal to the backing metal in the manner described results in such an amalgamation of the bearing metal with the bonding metal and the bonding metal with the backing metal that, for all practical purposes, the bond between the backing metal and the bearing metal is substantially uniform and complete throughout.

After the strip has thus been formed, it is cut up into pieces, each one of a size to produce a half-cylindrical bearing sleeve of the dimensions desired.

One very valuable feature of the method re" lates to the control and application of the molten bearing metal.

Preferably, the bearing metal is maintained in the supply chamber at a constant level by means of'a pump operating in a molten metal reservoir and an overflow from the supply chamber. The pump is arranged in the bottom portion of the reservoir and by its agitation of the molten metal prevents the settling or segregating of the heavier elements of the metal and any oxides which may appear in the supply chamber are overfiowed back into the reservoir.

Preferably, the atmosphere is excluded from the reservoir and de-oxidizing or reducing agents, such as sal ammoniac, charcoal, etc., are added to reduce the oxides and prevent oxidization of the metal.

Another feature relates to the passing of the backing strip through a body of the bearing metal in molten condition, both entering and leaving the metal below the top thereof, thus retiming the possibility of oxidation of the surface of the strip to a minimum.

Preferably, the backing strip is prepared for the addition of the bearing metal by being coated with a bonding metal, such as tin, and in the passing of the backing strip through the body of bearing metal, some bearing metal adheres to the back of the backing strip and another feature of the invention relates to simple scraper means for removing the bearing metal, except a thin film, from the back of the strip before the strip is cooled sufiiciently to congeal the bearing metal.-

The invention will be more readily understood by reference to the accompanying drawings forming part of this specification and in which:

Fig. 1 is a top plan view of a mechanism which has been found best adapted for practicing the invention;

Fig. 2 is a central, vertical, longitudinal section on the line 2-2 of Fig. l;

Fig. 3 is a transverse, vertical section on the line 3-3 of Figs. 1 and 2;

Fig. 4 is a transverse, vertical section on the line 44 of Fig. 2;

Fig. 5 is a sectional view showing a form alternative to that shown in Fig. 2; and

Fig. 6 is a perspective view of the product of the improved method.

The apparatus shown in the drawings is especially arranged and adapted for applying a layer of bearing metal 10 on a stripv of backing metal 11 to produce a bi-metal strip capable of being cut into suitable pieces or blanks 12 for use in making bearing linings.

The apparatus comprises an elongated bed or frame 13 having a channel or open trough 14 in its upper part and the strip 11 ofbacking metal is guided through the lower part of the channel,

and while passing through the channel the hearing metal coating 10, which is later to become the bearing metal lining of the bearing sleeves, is

applied.

The middle portion 15 of the length of the channel or trough 14 constitutes a chamber for containing molten bearing metal 16 and through the lower portion of which the strip 11 passes. The chamber is preferably substantially closed by a cover 17 to lessen or prevent oxidization of the hot metal and the metal is maintained at a desired temperature by suitable heating devices, such as gas burners 18 and 19,-arranged beneath the channel.

The strip is drawn or otherwise forced through the channel in the direction of the arrow 20. The strip 11- is guided through the chamber by means of horizontal guide grooves 21 in the inner surfaces of side filler pieces 22, as best shown in Fig. 3, and the entrance end of the chamber is closed by a block 23 above the strip 11 and a filler plate 24 btOW same.

The opposite or delivery end of the channel is partly closed by a block 25, a thin slot or channel 26 being arranged immediately above the strip 11 to permit the molten metal to be applied to the strip 11; in other words, the block 25 dams back the molten metal except as to the slot 26.

The strip 11 is heated as it passes through beneath the block 23 into the chamber by a heating device, such as a gas burner 27 arranged beneath the channel, and the delivery end of the apparatus is maintained at a desired temperature by a similar burner 28 beneath same. It is desirable that the strip be maintained at substantially the temperature of the molten metal especially during the passage through the chamber 15 in order that the'bond between the two may be as perfeet as possible. i

The strip 11 is protected from oxidation that is from contact with the air as it is heated by the burner 27, by reason of the fact that it fits closely in the guide slot formed by the filler block 23, the filler plate 24, and the sides of the channel.

The strip 11 is preferably coated with a bonding metal such as tin before it enters this apparatus and preferably before being tinned, it is roughened as by being etched with acid, all for the purpose of enhancing the perfectness of the bond.

The strip is passed through the molten metal always beneath the top thereof so that it is not brought into contact with any oxide which may be on the top. The side guides 22 terminate short of the block 25, as shown at 29, Fig. 2, thus leaving channels or connections around the edges of the stripbetween the upper part of the chamber 15 above the strip and the open space 30 below the strip and, consequently, the strip as it passes through the chamber is immersed in the molten metal and is always below the surface of same, especially as means to be later described are provided for maintaining a constant liquid level in the chamber at a point 31 above the location of the strip 11. I

As the strip passes through the hot metal in the chamber, the strip becomes of substantially the temperature of the molten metal, the tin coating becomes soft and amalgamates with the bearing metal and the conditions for producing a perfect bond are present.

It is desirable that as the bottom of the strip be free of bearing metal and be smooth and clean as it leaves the device, and to prevent the ad-- herence of bearing metal a transverse scraper 32 is provided, arranged below the block 25, filling the channel beneath the strip and provided with an edge 33 over which the strip passes and by which it is scraped clean, leaving the strip 11 coated on its bottom with an even smooth coating of tin. To best accomplish this result, it is desirable to hold the strip 11 down firmly on the scraper 32 and for this purpose a clamping member 34 is provided.

This clamping member 34 is in the form of a U-shaped bail surrounding the block 25. One end 35 of the member 34 is bent down and its lower end 36 is curved forward and rests on top of the strip 11. The opposite end 37 of the member 34 is bent down and its lower end 38 is likewise curved forward and rests on the top of the bearing metal coating 10. The member 34 is yieldingly held pressed down by means of springs 39 on upstanding studs 40 secured in the block It is advisable to gradually cool down the bearing metal as it is thinned down to the layer 10 and for this purpose the block 25 may have a channel or passage 44 extending longitudinally through same and through. which a cooling me dium such as water may flow. Preferably, the forward end of the passage 44 is closer to the strip than the rear end of same so as to make the cooling of the bearing metal quite gradual.

Preferably, the entrance end of the thin forming channel 26 is widened out vertically, as shown at 45, to provide an easy entrance for the molten metal beneath the block 25 to follow the strip 11 as it moves forward.

In addition to or in lieu of the cooling of the block 25 as described, the bi-metal strip may be chilled as it emerges from the machine, as indicated at 46, by means of a spray of water and air applied to the under or backing side of the strip.

The cooling effect of this spray is conducted by the bi-metal strip back into the delivery end of the slot 26 and, consequently, the bearing metal is chilled or set before it actually emerges. While this cooling of the strip is described as chilling the bearing metal, it should be understood that the strip is still hot enough so that the bearing metal is still malleable and can be further operated upon without fracture or destroying its in-v 48. The upper part of the reservoir 47 is con-' nected to the channel 14 by two connections, a"

lower delivery connection 49 and an upper return connection 50. The delivery connection 49 enters the channel 14 near its bottom and the return connection 50 nearer its top and constitutes an overflow back into the reservoir. Fonforcing' the molten metal from the reservoir into the chamber 15, a simple rotary impeller 51 may be provided in the lower end of the reservoir, the delivery end 52 of which is connected by a. riser 53 with the delivery connection 49.

The reservoir is preferably closed by a cover 54 which can carry a vertical shaft 55 upon the lower end of which the impeller is carried. The shaft can be provided with a belt pulley, 56 by which it can be rotated to operate the impeller. A suitable electric thermo-couple 57 may be inserted for indicating the temperature of the metal. The cover 54 may be provided with an opening through which deoxidized material or flux can be reservoir.

placed in the reservoir on the molten metal..

This method of maintaining the liquid level in the chamber 15 has many advantages. Very little, if any, oxidization can take place and if any oxides enter or are formed in the chamber 15, they rise to the-top away from the strip 11 and they are carried out of the overflow into the As the metal is forced from the bottom of the reservoir no oxides, which float on the top of the metal, are carried into the chamber 15. Furthermore, the agitation of the metal in the lower portion of the reservoir and thefact that it is lifted and forced into the chamber 15 prevents any separation of the different elements of the molten metal and maintains uniform quality throughout.

The chamber 58 whichsurrounds the impeller 51 may be hung from the cover- 54 and butted against-the lower end of the riser 53 so that the impeller and its housing can be freely removed with the cover.

In Fig. 5 there is illustrated an alternative means for denslfying or compressing the bi-metal strip and particularly the bearing metal layer 10. In the apparatus shown, a shorter block 59 is substituted for the longer block 25 first described but performing the same function of providing a thin channel 60 for forming the layer of bearing metal 10 on the strip 11 as the strip 11 is passed through the apparatus.

Similarly, a hold down yoke or member 61 is provided for holding the strip firmly down upon a scraper 62 for scraping the lower side of the strip. But instead of the channel in the block for a cooling medium, two cooling sprays 63 and 64 are provided, one directed upon the upper side of the strip and the other beneath. These sprays cool the strip and the cooling effect is conducted back far enough into'the delivery end of the channel through which the bi-metal strip emerges to properly set the bearing metal before it emerges.

Just beyond the sprays 63 and 64 is arranged a drawing device somewhat similar in construction to the delivery end of the forming machine but having a die slot or channel 65 which gradually narrows down from its entrance end 66 to its delivery end 67 and through which the bimetal strip is forced, such as being pulled through. i

The action is similar to that of drawing wire and either the whole strip or merely the bearing metal part can be effected. The object is to produce a bi-metal strip' of the kind described which shall be accurate as to dimensions within very narrow variations, perfectlysmooth on both fiat surfaces, and compressed to a degree beyond any compression it may be subjected to in use and in the best possible condition for the further operation of being formed into bi-metal bearing I sleeves.

We claim: 1. The herein described method of making a ing the side of the sheet metal strip opposite said layer substantially clean of bearing metal before the strip emerges from the machine.

3. The herein described method of making bimetal flat strips of steel and Babbitt metal for use in making bi-metal bearing sleeves, which consists in placing a flat strip of steel in motion lengthwise and while it is in motion, heating it to approximately the temperature of molten Babbitt metal, passing it horizontally through molten Babbitt metal, passing it through a mold opening greater in height than the thickness of the steel strip as it leaves the molten metal, whereby a layer of the molten metal passes out with the strip, gradually cooling the combined strip as it passes through the mold opening so that when the strip emerges the moltenmetal on the strip has congealed.

4. The invention as defined in claim 3, and chilling thebi-metal strip as it emerges.

5. The method as defined in claim 3, and while the strip is in motion forcing it through a die opening of such dimensions that the metal of the strip is compressed.

6. The method as deflnedin claim 3-, and while the strip is in motion forcing it through a die opening of such dimensions that the bearin metal of the strip is compressed.

7. The method as defined in claim 3, andwhile the strip is in motion forcing it through a die opening of such dimensions that the strip is accuratelysized as to thickness.-

8. In the herein described method of applying bearing metal to strips of backing metal, maintaining a chamber filled to a constant level with the bearing metal and maintaining a circulation of the molten metal through said chamber.

9. In the herein described method of applying bearing metal to strips of backing metal, maintaining a quantity of the bearing metal in a reservoir in a molten condition, constantly delivering a stream of the molten metal larger than the quantity used to a reservoir through which a backing strip is passed, the excess metal flowing back to the reservoir and by such action maintaining a uniform condition of the elements of the bearing metal throughout the mass.

10. The improved apparatus for applying molten metal to thin metal backing strips, which comprises a molten metal chamber, means for guiding a backing strip through the lower part of-the chamber, means for permitting a layer of the molten metal to pass out of the chamber on one side of the backing strip to form therewith a, bi-metal strip, and means for chilling the bi-metal strip asit emerges.

11. The invention as defined in claim 10, and means for scraping-the bearing metal from the opposite side of the strip before it is chilled.

12. The improvements herein described and comprising a molten metal chamber, means for 145' guiding a backing strip through the lower porbacking strip into motion endwise and while it is in motion heating the strip in a confined space to substantially the temperature of "the molten metal to be applied, and passing the strip from said confined space into a molten body of the metal to be applied below the surface thereof whereby oxidation of the strip and applied metal is reduced to a minimum.

BERGER STOCKFLETH. GLENN L. SHERWOOD. 

